A major focus of the polyolefin industry in recent years has been on the development of new catalysts that deliver new and improved products. In this regard, metallocene catalysts, for example, are now widely used to produce polyolefin polymers, such as polyethylene polymers. While there are many advantages to using metallocene catalysts in olefin polymerization, there remain significant challenges. For example, metallocene catalysts, in particular supported metallocene catalysts, may be more prone to causing reactor fouling which may cause disruption and premature shutdown of the reactor. This is particularly the case in particle forming processes, such as gas and slurry phase processes. Adding other reagents to the polymerization process, such as antifouling agents, antistatic agents or continuity additives/aids or continuity compositions, have been used to address such fouling issues.
In order to address reactor fouling problems caused by high activity metallocene catalysts, additives containing fatty amines have been added to the polymerization process, either separately or as part of a supported catalyst composition. However, the fatty amines have always contained a particulate inorganic material.
U.S. Pat. Appln. Pubn. No. US20010020072 discloses the use of a particular ethoxylated stearyl amine commercially available as AS-990 as an antistatic agent in olefin polymerization. AS-990 contains ethoxylated stearyl amine and particulate silica. The particulate silica is present at a level of about 10% by weight based on the weight of the ethoxylated stearyl amine and silica. The silica is added to improve the handling qualities of the ethoxylated stearyl amine which is a waxy solid at ambient temperature.
However, such fatty amine/silica compositions are time consuming to prepare and often show inconsistent behavior. Mixing solid or waxy components can result in the formation of agglomerates which may make the material difficult to dry to the low moisture levels desirable for use in olefin polymerization.
Therefore, despite the various polymerization catalysts known, challenges remain. Thus, it would be desirable to provide catalyst compositions useful in olefin polymerization that are advantageous to prepare and handle and are also capable of operating in a polymerization process continuously with enhanced reactor operability.